Nu-aminoethyl alkenyl succinamic acid deicer



up to 100 percent.

United States Patent '0 3,148,960 N AMEN OETHYL ALKENYL SUCCENAMIC ACID DEICER Myron Beck-er, Woodbury, N.J., assignor to Socony Mobil Gii'Conipany, Inc, a corporation of New York No Drawing. Filed July 11, 1961, Ser. No. 123,122 4 Claims. (Cl. 44-71) This invention relates to gasoline compositions adapted to improve the operation of internal combustion engines. It is more particularly concerned with motor fuels that provide improved engine operation under cool, humid weather conditions.

As is well known to those skilled in the art, frequent stalling of automobile engines, especially during the Warm- .up period, has been a common occurrence. This difficulty is most pronounced in postwar cars having automatic transmissions and a consequent limit on the maximum permissible idle speed but also occurs in cars not having automatic transmissions Stalling of this type, of course, is a definite safety hazard, as well as a decided inconvenience in frequent restarting of the engine.

It is now recognized that stalling during the warmup period is attributable to the formation of ice on the throttle plate and the carburetor barrel near it. The water which forms the ice does not come from the gasoline, i.e., as entrained water, but from the air that enters the carburetor. As has been'mentioned hereinbefore, stalling generally occurs in cool, humid weather, when the temperatures are above about 30 F. and below about 60 F. and the relative humidity is about 65 percent and higher, The most critical conditions are temperatures of 35-40 P. and 100 percent relative humidity.

As the gasoline evaporates in the carburetor, it reduces the temperature of the surrounding metal by as much as 50 F. Moisture in the incoming air comes in contact with these parts and begins to build up ice on thethrottle plate and in the carburetor barrel. The more moist this air is, the greater the buildup of ice. Then, when the engine is idled, the throttle plate closes and the ice chokes off the normal small flow of air through the small clearance between the throttle plate and the carburetor wall. This causes the engine to stall. The engine can usually be restarted when the heat from the exhaust manifold melts the ice sufliciently. However, stalling will continue until the engine is completely warmed up.

Carburetor icing occurs in many vehicles whencruising at speeds of 30-60 mph. Such icing is a pronounced problem in the case of certain trucks and cars equipped with carburetors having Venturi-type fuel-air mixing tubes (emulsion tubes). Such carburetors are found in trucks and in many European cars. The ice builds up on the tube and restricts the flow of air, thereby enriching the fuel mixture and reducing efiiciency. Eventually the engine may stall.

Gasoline is a mixture of hydrocarbons having an initial boiling point falling between about 75 F. and about 135 F. and an end-boiling point'falling between about 250 F. and about 450 F. The boiling range of the gasoline, of course, reflects on its volatility. Thus, a higher boiling gasoline will be less volatile and give less stalling difliculty. It has been proposed in the art that a gasoline having an ASTM mid-boiling (50%) point of 310 F. or higher will not be subject tostalling. Although this may be the case for a given series of gasolines, however, it is not the sole and controlling factor. Gasolines of higher mid-boiling point but a low initial boiling point (e.g. full boiling range gasolines) can induce stalling when the afore-mentioned stall-inducing atmospheric conditions are prevalent. Thus, any gasoline will give difliculty in damp, cool Weather. In modern engine operation, how- 3,148,960 Patented Sept. 15., 1964 up can be overcome simply and economically. It has been discovered that small amounts of'certain N-aminoethyl alkenylsuccinamic acids, when added to motor gasoline, will overcome stallingdifliculties attributable to carburetor icing.

Accordingly, it is an object of this invention to provide an improved motor fuel. Another object is to provide a motor fuel adapted to prevent stalling during engine warmup in cool, humid weather. A specific object is to provide an antistall gasoline containing certain alkenylsuccinamic acids. Other objects and advantages of this invention will become apparent to those skilled in the art, from the following detaileddescription.

In general, this invention provides a motor gasoline containing a small amount, suificient to inhibit stalling, of the N-aminoethyl alkenylsuccinamic acid of an-alkenyl succinic acid having the formula:

R-CH-C O OH CHz-COOH wherein R is an alkenyl radical containing between 8 and 16 carbon atoms.

The alkenyl succinamic acids contemplated herein are readily prepared by reacting equimolar amounts of an alkenyl succinic acid anhydrideand ethylenediamine, without formation of water of condensation and preferably, the reaction is carried out in the presence of an inert diluent, examples of which include-petroleum ether, benzene, xylene, and the like.

The alkenyl succinic acid anhydrides'useful in pro paring the alkenyl succinamic acids, have the structure:

whereinR'is an alkenyl radical having between 8 and 16 carbon atoms and preferably 'between 10 and 14 carbon atoms. lNon-limiting examples are o'ctenyl-succinic acid anhydride, diisobutenyl succinic acidanhydride, :2-met-hylheptenyl succinic acid anhydride, 4-ethylhexenyl succinic acid anhydride, nonenyl succinic acid anhydride, decenyl succinicacid anhydride, undecenyl succinic-acid anhydride, dodecenyl succinic acid anhydride, triisobutenyl succinic acid anhydride, tetrapropenyl succinic-acid anhydride, tetradecenyl succinic acidanhydride, and hexadecenyl succinic acid anhydride. The alkenyl succinamic acid can exist in either or both of the following strucwherein R isalkenylwhen R' is hydrogen andR' is alkenyl whenR islhydroge The amount of N-a-minoethyl-alkenylsuccinamic acid that is added tothe motor-gasoline will vary between about 0.002 percent and about 0.5 percent, by weight, of the gasoline. In preferred practice, amounts vary-ing between about 0.004 percent and 0.05 .percent, by weight, are used.

The antistall additives of theinvention may be vused in the gasoline along with other antist-all additionagents or other additives designed to impart other improved properties thereto. Thus, anti-knock agents, pre-ignition a,14.s,seo

inhibitors, anti-rust agents, metal-deactivators, dyes, antioxidants, detergents, etc., may be present in the gasoline. Also, the gasoline may contain a small amount, from about 0.01 percent to about 1 percent, by weight, of a solvent oil or upperlube. Suitable oils, for example, include Coastal and Mid-Continent distillate oils having viscosities within the range of from about 50 to about 500 S.U.S. at 100 F. Synthetic oils, such as diester oils, polyalkylene glycols, silicones, phosphate esters, poly-propylenes, polybutylenes and the like, may also be used.

The following examples are for the purpose of illustrating this invention and demonstrating the effectiveness thereof. This invention is not to be limited to the specific compositions set forth in the examples ,or to the operations and manipulations involved. Other materials and formulations as described, hereinbefore can be used, as 7 those skilled in the art will readily understand.

The ability of an additive .to inhibit stalling is demonstrated in the following tests:

CHEVROLET ENGINE TEST A standard Chevrolet engine was equipped with a Holley single downdraft carburetor which was mounted in a cold box refrigerated to about 40 F. A thermocouple was attached to the throttle plate shaft to record the plate temperature and a /2 inch insulating gasket placed between the carburetor and manifold to prevent heat conduction. An asbestos sheet covered the entire manifold system to shield the carburetor from convection and radiation. A spray chamber and an ice tower were used to saturate the incoming air with moisture and to cool the air to about 35 F. before it enteredthe carburetor.

In conducting a test, the engine was first run for about 10 minutes at 2000 rpm. to bring the engine temperature to equilibrium. The engine was then shut off. When the throttle shaft temperature rose to 40 F., the engine was restarted with the idle speed set at 450 r.p.m. so that the base fuel stalled at idle in 10 seconds or less after a run-time of to 50 seconds. Run time means the time that the engine was run at 2000 rpm. before returning to idle.

All the runs were started when the throttle shaft reached 40 F. At the instant of starting, the throttle arm was moved to the 2000 rpm. position and a stop watch started. At the end of the selected run-time, the

throttle arm was moved to the idle position. The time required to stall was recorded. Several tests were made at each run-time and averaged.

In evaluating an additive, the base fuel was first tested followed by several concentrations of the additive. The system was flushed between tests with thefuel to be run next. Any improvement caused by the additive was reflected in a longer run-time (as compared to the base fuel) to cause stalling in 10 seconds or less when the engine was idled. The more effective the additive ,the longer the run-time.

HILLMAN-MINX ENGINE TEST A downdraft Solex FAT carburetor was mounted on a standard 1953 Hillman-Minx engine. The engine was connected to a 7.5 horsepower induction motor and operated under load at 2800 r.p.m. This was equivalent to driving at about miles per hour.

The Solex carburetor was especially prone to icing on its spraying well which is located in the center of the carburetor throat. The spraying well is a cylindrical metal tube with apertures through which a fuel-air mixture is sprayed into the carburetor throat. Evaporation of the fuel refrigerates the spraying well.

As ice formed on the well it restricted the flow of air through the carburetor and caused a drop in pressure. This pressure change was recorded by a manometer connected above and below the point of ice deposition. Temperatures at this point were measured by a thermocouple attached to the well. The entire carburetor was enclosed in an asbestos chamber that was connected to an ice tower. Air at 34-37" F and l00 percent relative humidity was passed through the carburetor at constant velocity.

In conducting a test the engine was first run until the spraying well reached an equilibrium temperature of about 20-25 F. The fuel flow was then stopped and the engine was driven by the induction motor until the spraying well reached 45 F. (warm ambient air wasadmitted to the carburetor during this period). Fuel flow was now restored to the engine and the run was started. As the engine operated under load, ice deposited on the spraying well. The pressure drop across the ice formation was recorded at one minute intervals for 20 minutes. The run was concluded. Several tests were made on each fuel blend and the results were averaged.

A fuel rating was obtained by using these pressure readings to calculate the percentage of the carburetor throat area that would be blocked with ice after 20 minutes. The percent of annular area in the carburetor that is blocked by ice determines the amount of pressure drop across-- the annular opening in any given installation. Thus, for each carburetor, the amount of throat area blocked by ice is related to the amount of pressure drop above and below the point of ice deposition. The relationship between pressure drop and area blocked was determined to calibrate the carburetor as follows:

A series of flanged cylinders were prepared, which fitted over the emulsion tube and blocked a portion of the annular opening. Each tube had a different, but known size flange. Thus, it was known what fraction of the annular area was blocked by each flange. The engine was operated with a flanged cylinder in the carburetor and the amount of pressure drop was noted and recorded. This operation was repeated with each flange.

For the data, thus obtained, the relationship between pressure drop and amount of throat area blocked was plotted. Then, when runs were made using blank fuel 'or inhibited (test) fuel, but with no flanged inserts in the carburetor, the throat area blocked by ice was determined from the amount of pressure drop. The area blocked after the 20-minute run is obtained from the summation of the one-minute observations.

It will be appreciated, of course, that calibration curves will vary with each carburetor, but any carburetor can be readily calibrated as aforedescribed. As is the case in many test procedures, results can vary from time .to time, because of slight variations in test conditions, vapor pressure of fuel, and even techniques of individual operators. Thus, each day a test run is made, a blank fuel should be run. This provides a reference point, so that even if values determined may not be finite, comparison of a test fuel results with the result on the blank fuel gives a positive order of magnitude, i.e., one can say for example that an additive cut the amount of ice formation by some certain percentage.

Gasoline A was a blend, by volume, of 66 percent catalytically cracked gasoline, 6 percent natural gasoline, 12 percent benzene, 8 percent toluene, and 8 percent butane. It had an A.S.T.M. boiling range of 87 F. to 385 F., with a mid-boiling point of 197 F. Gasoline B was a blend by volume of 66 percent catalytically cracked gasoline, 6 percent natural gasoline, 12 percent benzene, 8 percent toluene and 8 percent butane. It had an A.S.T.M. boiling range of 85 F. to 402 F. with a mid-boiling point of 198 F.

PREPARATION OF N-AMINOETHYL TETRA- PROPENYL SUCCINAMIC AClD Ethylenediamine (12.0 g., 0.2 mol) was added to tetrapropenylsuccinic anhydride (53.2 g., 0.2 mol) in petroleum ether at 1.5-) C. during 55 minutes. The mixture was allowed to warm to room temperature with stirring. Petroleum ether cc.) was then added and a precipitate was formed. The mixture was made just acid to litmus with 20% aqueous hydochloric acid and the precipitate dissolved.

The organic layer was Washed with salt water, filtered, the petroleum ether was removed by distillation and vacuum distillation was used to remove final traces of the petroleum ether, thereby providing N-aminoethyl tetrapropenyl succinamic acid.

Blends of the N-aminoethyl tetrapropenyl succinamic acid in gasoline A were subjected to the Chevrolet Engine Test. Pertinent data and test results are set forth in Table I.

Table I Run Time to Sec.

Stall Time (See) Concn N-aminoethyl Tetrapropenylsuccin- Gasoline amic Acid, Wt. Percent Blank 0.0L 0 02 Percent Annular Area Blocked with Ice After 20 Minutes Additive Oouon, Wt. Percent Gasoline Blank 0 01 0.05.

mum

It will be apparent from the foregoing data in Tables I and II that the additives of this invention are effective anti-stall agents for gasolines'.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

l. A motor gasoline containing a small amount, sufficient to inhibit stalling, of an alkenyl succinamic acid of the formula:

wherein R is an alkenyl group when R is hydrogen, and R is an alkenyl group when R is hydrogen, and the alkenyl group contains eight to sixteen carbon atoms.

2. A motor gasoline, as defined in claim 1, which con tains the alkenyl succinamic acid in an amount of from about 0.002 to about 0.5 percent by weight of the gasoline.

3. A motor gasoline, as defined in claim 1, wherein the alkenyl group is tetrapropenyl.

4. A motor gasoline containing about 0.002 to about 0.5 percent based on the weight of the gasoline, of N- arninoethyl tetrapropenyl succinamic acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,982,629 Andress et al. May 2, 1961 2,982,632 Andress May 2, 1961 2,982,633 Andress May 2, 1961 2,982,634 Nygaard May 2, 1961 

1. A MOTOR GASOLINE CONTAINING A SMALL AMOUNT, SUFFICIENT TO INHIBIT STALLING, OF AN ALKENYL SUCCINIAMIC ACID OF THE FORMULA: 